Measurement system

Abstract

A contact-free, optical measurement system for determining the precision with which an article rotates. A reflective surface is secured to a rotating surface and a light source, such as a laser, is disposed thereabove. A target is likewise secured in association with the light source to receive the reflected light from the spinning surface. In this manner, any dynamic angular misalignment, or wobble, in the spinning surface will be manifested in movement of the reflected light upon the target. The degree of wobble of the spinning surface may then be readily ascertained.

I claim: 
     
       1. Apparatus for the measurement of angular deflection of a spinning surface comprising: a light source for emitting a beam of light toward said surface to be measured for generating a reflection therefrom;   means for supporting said light source, said support means comprising means for permitting said light source to assume a select orientation;   reflective matter secured to said spinning surface;   a reflection target secured relative to said light source for displaying light reflected from said surface;   means associated with said target for determining the location and movement of said reflected light upon said target during the spin of said spinning surface as an indication of angular deflection thereof;   said select orientation being generally parallel to the pull of gravity; and   wherein said support means comprises a gimbal mounting fixture adapted for securing said light source therein and permitting said light source to depend therefrom and assume an angular orientation parallel with the pull gravity.   
     
     
       2. The apparatus as set forth in claim 1 wherein said light source comprises a laser. 
     
     
       3. The apparatus as set forth in claim 2 wherein said laser has a self-contained power source. 
     
     
       4. The apparatus as set forth in claim 1 wherein said spinning surface comprises a semi-conductor manufacturing system spinner and said reflective matter disposed upon said spinning surface comprises a semi-conductor wafer. 
     
     
       5. The apparatus as set forth in claim 4 wherein said spinner is disposed within a housing adapted for applying fluid to said wafer and the subsequent spinning thereof to evenly distribute said fluid across the surface of said wafer along a notional plane substantially perpendicular to the pull of gravity. 
     
     
       6. Apparatus for the measurement of angular deflection of a spinning surface comprising: a light source for emitting a beam of light toward said surface to be measured for generating a reflection therefrom;   means for supporting said light source, said support means comprising means for permitting said light source to assume a select orientation;   reflective matter secured to said spinning surface;   a reflection target secured relative to said light source for displaying light reflected from said surface;   means associated with said target for determining the location and movement of said reflected light upon said target during the spin of said spinning surface as an indication of angular deflection thereof;   said reflection target comprising a planar member secured to said light source; and   wherein said means associated with said target for determining the deviation of said reflected light comprises indicia formed upon said target facilitating the visual measurement of any movement of said reflected light beam thereupon.   
     
     
       7. The apparatus as set forth in claim 6 wherein said target includes an aperture formed therethrough adapted for securement over an end of said light source for receiving a beam of light from said light source therethrough. 
     
     
       8. A method for measuring angular deflection of a spinning surface comprising the steps of: providing a light source for generating a beam of light toward said surface to be measured for reflection therefrom;   supporting said light source relative to said spinning surface with a select angular orientation relative thereto;   disposing reflective matter upon said spinning surface;   providing a reflection target for receiving the reflection of light from said reflective matter;   securing said reflection target relative to said light source for displaying light reflected from said target;   providing means associated with said target for determining a movement of said reflected light upon said target during the spin of said spinning surface; and   wherein the step of supporting said light source with a select angular orientation includes the step of suspending said light source and allowing the pull of gravity to establish said select angular orientation.   
     
     
       9. The method as set forth in claim 8 wherein said step of providing a light source comprises the step of providing a laser to produce collimated light. 
     
     
       10. The method as set forth in claim 9 wherein said step of providing a laser includes the stop of providing said laser with a self-contained power source. 
     
     
       11. The method as set forth in claim 8 wherein said step of supporting said light source comprises the step of providing a gimbal mounting fixture adapted for securing said light source therein and permitting said light source to depend therefrom and assume an angular orientation parallel with the pull of gravity. 
     
     
       12. The method as set forth in claim 8 wherein said step of disposing reflective matter upon said spinning surface comprises the step of providing a semi-conductor wafer and mounting said wafer to said spinner. 
     
     
       13. The method as set forth in claim 12 and further including the step of disposing said spinner within a housing adapted for applying liquid to said wafer and the step of subsequent spinning said wafer to evenly distribute said liquid across the surface of said wafer. 
     
     
       14. A method for measuring angular deflection of a spinning surface comprising the steps of: providing a light source for generating a beam of light toward said surface to be measured for reflection therefrom;   supporting said light source relative to said spinning surface with a select angular orientation relative thereto;   disposing reflective matter upon said spinning surface;   providing a reflection target for receiving the reflection of light from said reflective matter;   securing said reflection target relative to said light source for displaying light reflected from said target;   providing means associated with said target for determining a movement of said reflected light upon said target during the spin of said spinning surface;   wherein said step of providing a refection target comprises the step of mounting a planar member to said light source; and   wherein said step of providing a reflection target comprises the step of mounting a planar member to said light source; and   wherein said step of providing means associated with said target for determining the deviation of said reflected light comprises the step of forming indicia upon said target to facilitate the visual measurement of any movement of the reflected light beam thereupon.   
     
     
       15. The method as set forth in claim 14 wherein said step of mounting said planar member includes the step of forming a hole there and securing said hole over an end of said light source for receiving a beam of light from said light source therethrough.